It’s what historians of 9/11 – which is what the activists and investigators essentially are – value most: the paper trail. Documents, statements, memos. This is the grist of history. And if some of the 9/11 activists can tend, sometimes, towards the obsessive, it’s generally an obsession with data. And to have that data withheld? It’s murder.

So when, at the tail end of LibertyFest, longtime 9/11 activist Luke Rudkowski tells me of the 2.5 terabytes of data from the Able Dangerterror investigations that were deleted, it’s with genuine pain in his eyes. It’s a Ming vase that’s smashed on the floor. It’s Wayne Rooney looking at a squashed banana. It’s a tragedy.

I asked Rudkowski what the “Truthers” were planning for the day. “This year, we’re all about paying our respects to the dead. We’re sending out a solemn message: we don’t know what happened on 9/11, yes we have questions, but on the day we’re not asking them. We’re going to stand in respectful silence.”

Luke Rudkowski Photograph: Charlie Skelton

But on the night before, Rudkowski is happy to ask. Why, from the 78 security cameras that surround the Pentagon, have we been shown just a few blurry frames? Why has the FBI classified its official investigation into the fact that some of the hijackers were trained at US military bases…?

And what would he say to those who’d scoff at asking such questions? “I’d say, look at the evidence and make up your own mind. And remember, 9/11 is a gigantic event that’s going to affect us all for the next hundred years, but it’s an event a lot of people know very little about.”

And with that, I slid away from the party, and bought some toothpaste from a late night store. I’m not going to mark the tenth anniversary of 9/11 with dirty teeth. I’m glad that the New York Truthers aren’t planning anything big and brash for the anniversary. The living will still have their questions, documents will need to be declassified, evidence sifted and lies challenged, but the anniversary of 9/11 is about the dead. The truth can take the day off.